Treatment of sodium calcium cyanide



Patented Feb. 20, 1934 UNITED STATES PATENT OFFICE TREATMENT OF SODIUMCALCIUM CYANIDE No Drawing.

Application August 1, 1930 Serial No. 472,482

3 Claims.

This invention relates to a process for treating sodium calcium cyanidewith liquid anhydrous ammonia to produce sodium cyanide and calciumcyanide.

The sodium calcium cyanide may be produced by methods described in mycopending application Ser. No. 623,026, filed July 16, 1932, or by othermeans.

According to that application, when the elements calcium, sodium, carbonand nitrogen, or materials capable of producing these elements, arepresent in a reaction zone in the proportions of at least one atom ofcalcium, two atoms of sodium, four atoms of carbon and four atoms ofnitrogen and are intimately mixed and heated to a temperature above 13500., preferably 1400 to 1450 0., sodium calcium cyanide will be formedaccording to the following equations:--

In accordance with the present invention, I mix the crude sodium calciumcyanide with liquid anhydrous ammonia. The ammonia will dissociate thesodium calcium cyanide and the sodium cyanide will pass into solution,while the calcium cyanide and other forms of calcium present will remainin the insoluble residue. The solution and insolubles may be readilyseparated by filtration, the ammonia evaporated from the solution,leaving substantially pure sodium cyanide, and the ammonia likewiseevaporated from the insoluble residue, leaving a product containing alarge percentage of calcium cyanide which may be either used as such asa fumigating material, or for other purposes, or may be converted tosodium cyanide, for example, by transposition with sodium carbonate,sodium hydroxid, sodium oxalate or other suitable salts, or may beconverted to other cyanide derivatives by obvious means.

The ammonia evaporated as described may, of course, be recondensed andused again. Obviously, since evaporation and liquefaction are reciprocaloperations, they may be accomplished simultaneously in practice in asuitable apparatus; as, for example, a vacuum evaporator, in which thesolution from which the ammonia is to be evaporated is kept underpartial vacuum while the ammonia vapor to be liquefied is compressed inwhat are ordinarily the steam coils of the same apparatus.

What I claim is: I

1. The process of producing sodium cyanide from sodium calcium cyanidewhich consists in mixing the latter with liquid anhydrous ammonia,separating the solution from the insolubles, and separating thecontained sodium cyanide from the solution.

2. The process of producing sodium cyanide and calcium cyanide fromsodium calcium cyanide which consists in mixing the latter with liquidanhydrous ammonia, separating the solution from the insolubles,separating the contained sodium cyanide from the solution, andevaporating the ammonia from the said insolubles.

3. The process of producing sodium cyanide from sodium calcium cyanidewhich consists in mixing the latter with liquid anhydrous ammonia,separating the solution from the insolubles, separating the containedsodium cyanide from the solution, evaporating the ammonia from theinsolubles, converting the contained calcium cyanide to sodium cyanidein aqueous solution by suitable means, and recovering the sodium cyanidefrom the aqueous solution.

EDWARD J. PRANKE.

